TOPN not working

[admin_xlsior]

When I have this kind of data relationship:

Then I create a Top 2 measure based on Item group like this:

Top 2 Amount by item group = CALCULATE(SUM(Transactions[amount]),
                                    TOPN(2,
                                        'Item groups', 'Item groups'[Group],ASC
                                ), VALUES('Item groups'[Group])
)

Whereby what I want to show is the TOP 2 item group, what is the mistake, because currently still all item group come out.

The value and the ranking is correct though, only it doesn;t only show 2 of my item group.

[v-chuncz-msft]

@admin_xlsior 

You may check the cross filter direction between tables.